Artificial sausage casings made entirely of regenerated cellulose and fibrous casings have been widely used in the processing of frankfurters and salamis for a number of years. The basic process for the manufacture of small casings of regenerated cellulose is known as the viscose process and comprises extruding viscose, which is a solution of sodium cellulose xanthate in caustic soda, through an annular die to form a tubular casing, coagulating the casing in a coagulating bath, e.g., an acid-salt bath, and then subsequently regenerating the cellulose. After regeneration of the cellulose, the casing is plasticized, suitably with glycerin or other plasticizing agent, and dried to a moisture content of from about 8 - 10%. The casing coming from the dryer is wound on a reel. The casing then is shirred which comprises compacting substantial lengths of casing, e.g., 100 - 160 feet, into a few inches, e.g., 8 - 18 inches. After shirring, the casing is packaged.
In manufacturing fibrous casings, a paper web, usually manila hemp paper having a weight of from about 12 - 16 pounds per ream, is impregnated with viscose, coagulated, and the cellulose regenerated. The casing is plasticized, suitably with glycerin, and dried. The casing is sold to the meat processor in cut lengths of about 12 - 30 inches or in reel form or sometimes in shirred form as is done with the smaller regenerated cellulose casing.
Regenerated cellulose casing has a tendency to be brittle and often when flexed develops pinholes or cracks making it unsuited for stuffing with a meat emulsion. In the past, there has been a substantial loss of casing due to breakage of the casing at the shirring machine or substantial stuffing problems due to pinholes in the casing. Many commercial artificial casings also have a tendency to adhere to sausages and these sausage casings are difficult to peel from the sausage. In other words, these casings do not have "rapid peel" characteristics. By rapid peel characteristics it is meant that the casing can be readily peeled from the weiners by machine with very few peeling misses and with little scarring of the weiner.